Chlorophyll

The discovery of chlorophyll marked a significant advancement in plant chemistry, identifying the substance responsible for the green pigmentation in plants that also plays a crucial role in photosynthesis by trapping sunlight and converting it into energy, which in turn creates plant tissue and oxygen.
 Pierre Joseph Pelletier and Joseph Bienaimé Caventou France 1817 Chlorophyll

The discovery of chlorophyll marked a significant advancement in plant chemistry, identifying the substance responsible for the green pigmentation in plants that also plays a crucial role in photosynthesis by trapping sunlight and converting it into energy, which in turn creates plant tissue and oxygen.